Paints & Coatings
Paint and coatings manufacturing depends on particle size reduction to disperse pigments evenly through a liquid carrier, producing consistent color, gloss, and coverage. Norstone, Inc. supplies grinding media, dispersing blades, and processing equipment for paint milling and coatings dispersion, covering the full range from initial pigment wetting through fine particle size reduction. Media and equipment selection depends on the pigment being processed, the target particle size, and the finish quality required in the end product.
Recommended Products
Paints and coatings production generally moves through two stages, each supported by different Norstone, Inc. product lines. Initial pigment wetting and deagglomeration is typically handled by High Shear Impellers or Turbine Blades, which apply high shear to break apart pigment agglomerates and disperse them into the liquid carrier. Once pigment is wetted, fine particle size reduction is carried out in a Mill using grinding media matched to the pigment's hardness and the target particle size.
Grinding media selection for paint milling covers most of the seven material families Norstone, Inc. supplies. Glass Grinding Media is a common starting point for general purpose paint dispersion, offering a cost-efficient option for softer pigments and standard finish requirements. Zirconia Grinding Media is specified where finer particle size or reduced contamination is required for higher-grade finishes. Steel Grinding Media is used in some paint milling applications, but is generally reserved for darker colors or applications where a degree of metal contamination does not affect the finished product, since lighter or more color-sensitive formulations are more commonly milled with glass, zirconia, or exotic media instead. Silicon Carbide grinding media, within the Exotic family, is specified for harder or more abrasive pigments requiring greater wear resistance than the standard ceramic families provide.
Choosing Between Media Options
Media selection for a paint milling application generally starts with the pigment's hardness and abrasiveness. Softer, less abrasive pigments are compatible with a wider range of media families, including glass, which keeps material cost lower for high-volume production runs. Harder or more abrasive pigments wear softer media more quickly, which increases media consumption and can introduce media fragments into the finished product, so a harder media family such as zirconia or silicon carbide is generally specified instead.
Color sensitivity is the second major factor. Light colors and white bases are generally milled with media that introduces minimal visible contamination, favoring glass, zirconia, or ceramic families over steel media. Darker colors and black formulations tolerate a wider range of media options, since minor contamination is less likely to visibly affect the finished color. This is why steel grinding media sees more use in darker paint formulations than in lighter or white-based ones.
Finish quality requirements also affect media size selection. Coarser media generally produces a faster initial size reduction but a wider particle size distribution, while finer media produces a narrower distribution suited to higher-gloss or more color-consistent finishes, at the cost of a longer milling cycle. The Grinding Media Selection Guide provides a full comparison across all seven material families for narrowing these options against a specific formulation.
Equipment Considerations
Mill selection for paint and coatings applications generally comes down to batch consistency and production volume. A Horizontal Mill configuration is commonly specified for continuous processing of higher-viscosity paint formulations, while smaller batch runs or sample formulations may use a Basket Mill configuration instead. Mixers are used downstream of milling for final blending, tinting, and staging before packaging.
Applicable dispersing blade selection also depends on batch viscosity. High Shear Impellers are generally specified for standard paint viscosities, while High Vane Impellers are specified where a gentler, more uniform dispersion is needed across the full batch without the higher shear a High Shear Impeller generates.